Telephone-exchange system



Nov. 11 1924.

C. B. FOWLER TELEPHONE EXCHANGE SYSTEM Filed Dec. 4, 1919 2 Sheena-Sheet 1 Nav, 11, 1924 l,54,847

c. B. FOWLER TELEPHONE EXCHANGE SYSTEM Filed Dec. 4, 1919 2 Sheets-Sheo Inh /are/vce 5. FGW/ef (gl-41,4 v l, j /4/04 Patented Nov. l1, 1924.

CLARENCE B. FOVJLER, F YORK, N. Y., ASSIQ'E'NGR TO 'WESTERN ELECTRC COM- PANY, NCORPORATED, OF NEW' YORK, N. A CORPORATION OF NEW YORK.

YTELE?HONE-EXCHA1:16311 SYSTEM.

Application filed December 4, 1919. Serial No. 342,341.

To ail-'whom t may concern.' the circuits employed in carrying out the in- Be it known that I, CLARENCE B. Fownnn, vention. Fig. 1 shows the circuit arrangea citizen of the United States, residing at ment and apparatus employed at the manual New York, in the county ot New York, State excl'iange and Fig. 2 that at the automatic 5 ofNew York, have invented certain new and exchange. 60 useful Improvements in rlelephone-Ex Referring to Fig. 1 of the drawings, F change Systems, of which the following is represents a dialing or calling cord circuit a full, clear, concise, and exact description. ot which there is one at each operators posi- This invention relates to telephone extion.r and A a connecting cord circuit ot' change systems, and more particularly to which there are a plurality at each oper- 65 such systems in which connections are to be ators position. Each operator has access to established between telephone lines termia plurality of trunk hunting switches C. nating at a manual exchange and telephone sociated vwith the switchboard end ot each lines terminating at an automatic exchange. trunk hunting switch C is a pair ot jacks.

The invention is especially directed, h-owone termed a connecting jack t and the other 70 ever, toward a system in which a toll opadialing or calling jack 1. The other enol of erator may, in response to a call received the trunk hunting switch terminates in over a calling' line terminating in her p'osibrushes, such as 30, 31 and 32, arranged to tion, through trunli( circuits automatically cooperate with terminals 34, and 36 of a 20 select the desired line terminating in an autrunk circuit extending from the manual to 75 tomatic exchange. the automatic exchange. Normally, the diallu systems ot this nature it is desirable ing cord F rests in an idle dialing jack 1.

to have as little apparatus as possible conlfilhen the loperator desires to call a subnected across or in the talking conductors in Scriber in the automatic exchange, insertion order to bring the speech transmission up to oit calling cord A in the connecting jack 4. S0' as high a standard as possible. Where aucauses an idle trunk to the automatic extomatic switches are utilized ttor connecting change, the outgoing end ot which is shown acalling line with a called line, it is the in F ig. 1, to be selected.

usual practice to have an impulse or step- Fig, 2 represents diagrannnatically the S0 ping relay pern'ianently connected to one or incoming end ot the trunk circuit and con- 55 both ot the talking conductors of the con- Hector circuit at the automatic exchange,

nccting circuit, which naturally reduces the while E represents a subscribers station terspeech transmission. minating thereat. The apparatus shown to It is, therefore, the object ot this inventhe right of the dotted line 0*() is assotion to provide an improved system for ciated with the connector while that to the :lo rapidly establishing connections between a lett is associated with the incoming end ot' manual or toll telephone exchange and an the trunk circuit.

automatic telephone exchange, and for pro- Assume that the operator at the manual viding talking connections between them of tor toll exchange in answering' a call re- 40 maximum etliciency. ceived in the usual manner over a suitable o5 ln attaining the objects of this invention, line circuit not shown) terminating therean automatically selected trunk circuit, havat., ascertains that a connection desired ing an impulse repeating means associated 'with substation E on a line terminating at therewitlnis employed for extending the conthe automatic exchange. rihe insertion or' nections from a manual or toll to an autoplug 19 into jack 4, operates relay 14 and 100 matic exchange, said impulse repeating lights lamp li" over a circuit established means being disassociated :from said trunk from grounded battery, through the lamp circuit after' the connection has been estab- 17, the resistance 18, the sleeve contacts of lished. plug 19 and jacr il, and winding ot relai.T

Other features which result from or are in- 11i, to ground. Upon cnergization of relay 105 @ident to the main object above noted will 1-1, all of its armatures are attracted, thus appear during the description of the inestablishing circuits for relay 8 and motor vention. magnet 10. The armatures of relay 14 are Figs. 1 and 2, with Fig. 1 at the lett, diaso arranged that contact o, makes before grammatcally indicate the apparatus and contact o. The circuit tor relay 8 extends 110 from grounded battery, front contact and inner armature of relay 14, winding of relay 8, through the tip contacts of jack 1 and plug 20,`to ground. Energization of relay 8 opens the tip and ring conductors of the trunk hunting circ-uit leading to the cord circuit, thus preventing the connection of ground thereto during dialing, and connects the impulse sender B to the tip and ring conductors leading to the brushes. lf the switch wiper 32 is resting on a busy contact 36, ground will be present thereon. Ground will then be connected to both sides of the winding of relay 9, thus preventing its operation. Motor magnet 10 will, however, be energized over the following path: grounded battery, winding of magnet 10, armature and/back contact thereof, back Contact and lower inner armature of relay 9, brush 32, to grounded terminal 36. Energization of motor magnet 10 moves the brushes 30, 31 and 32 until an idle or non-grounded trunk circuit is found. As soon as an idle trunk circuit is found, relay 9 is energized over the following path: ground, front contact and -middle armature of relay 14, winding of relay 9, outer armature and front contact of relay 14, back contact and armature of magnet 10, and winding thereof, to grounded battery. Motor magnet 10 is so adjusted that it will not operate in series with relay 9. Operation of relay 9 extends theftip and ring conductors of the trunk hunting `circuit C through to the brushes and 31, and connects ground to the brush 32. Energization of relay 9 also l completes a circuit at its lower outer armature and front Contact for the supervisory lamp 49 at the operators position thus in dicating that the impulses may be sent. As soon as relay 9 is operated, relay 41 is en ergized over the following path: grounded battery, winding of relay 41, back contact and inner armature of relay 42, terminal 34, brush 30, upper armatures and front contacts of relays 9 and 8, sleeve of jack 1 sleeve of plug 20, and the normally closed contacts 51 of impulse sender B, to ground.

Energization of relay 9 closed paths simul- 'taneously for relays 41 and 42, but relay 42 is of the slow-operating type and its circuit is interrupted at the armature and back Contact of relay 41 before it is operated.

rShe operator actuates the impulse sender B in the usual manner to send out the imAA pulses necessary to call the desired subscriber E. rlhe contacts of the impulse sender B are so arranged that contact 50 is closed before contact 51 is opened, and remains closed during the sending of impulses. The first actuation of the impulse sender B closes the Contact 50 to operate relay 40 overa circuit established from grounded battery, through the winding of rela-y 40, back contact and Outer armature of relay 42, terminal 35', brush 31, upper inner armatures and front contacts of relays 9 4and 8, ring of jack 1, ring of plug 20, contact 50 of sender B, to ground. Energization of relay 40, connects ground to the relay 109 of the trunk circuit at the automatic exchange causing its energization over the following path: ground, front contact and lower inner armature of relay 9, brush 32, terminal 36, alternate contacts of relay 40, front contact and armature of relay 41, resistance 45, and winding of relay 109, to grounded battery. Relay 109 attracts its armature and completes a circuit at its armature and front contact for slow-release relay 110. At each interruption of the circuit for relay 41, at the cont-act 51, relay 41 will be deenergized causing in turn the interruption of the circuit for relay 109 at the automatic exchange. v

At the rst retraction of the armature of relay 109, a circuit is completed from battery, through rotary stepping magnet 111 and the escape magnet 112 in parallel, and thence through wiper 113. A circuit is also completed from battery, through the release relay 114 to the wiper 113, the circuits being continued to ground through the front contact and armature of relay 110 and back contact and armature of relay 109. Magnet 111 and relays 112 and 114 will be energized. Relay 114 will now be held up over a circuit extending through both front contacts and the armature of relay 110. to ground through resistance 115. This resistance 115,.how ever, is so high as not to hold up the armature of magnet 111 or relay 112. Thus, when the relay 109 next attracts its arma-y ture, the armature of rotary magnet 111 will drop back. Relay 110 being slow to release will, however, hold up during brief interruptions in its circuit at the back contact of relay 109. Thus with each interruption in the line circuit at the operators sending device, the brushes 116, 11'? and 118 of the trunk switch will be moved from one group of contacts associated therewith to the next. Any step-by-step two-movement switch may be employed with the circuits shown. A switch of this general character is shown in the Patent No. 815,176 of March 13, 1906, to Keith and Erickson. However. in the description of the present invention, the stepping magnet which first operates is described as a 4rotary magnet, that is, an around-and-up switch instead of an up-andaround switch shown in Keith et al. A switch of this character is shown in Patent No. 1,252,420 of January 8, 1918, to Oscar F. Forsberg. The side switch employed in the `present invention may be of the type shown in the Keith et al patent or of the type similar to that disclosed in the Forsberg patent.

Resuming now the description of the opelatien. 0f. the Circuits. when the last impulse is. Sent, relay 4.0, deenerefizes, but relays 4l and 109 will remain energized, the latter due to the make-before-break contact being used on relay 40, thus holding open they circuit fer theslow release relay 112 and for the rot-ary magnet 111. The switch brushes will be stopped in operative relation to, in the present instance, just below the group of trunk contacts desired. lVhen the relay 112 attracted its armature, it completed a circuit for the escape magnet 119 which now retracts its armature and moves the side switch wipers to position 2. In position 2, a circuit is completed from battery, through the test relay 120, side switch wiper 121 and the normally closed contact 122. Contact 122 opens on the irst vertical step. 'lhe test relay in attractingV its armature,l completes a circuit for the escape magnet 119. A circuit is also completed from battery,

through the vertical stepping magnet 1;.3., oil-normal contact 12a, wiper 125 and interrupter 126, to ground. The circuit crt the vertical stepping magnet will be alternately opened and closed by the interrupter 126, causing the selector brushes 116. 111- and 113 to move from trunk to trunk of the selected group. rlhe lower or test contact of all busy trunks will be connected to ground through resistance 115 by a circuit extendingA through the brush 113 and side switch wipers 121 and 113 of the selector switches associated `with said busy trunks. Thus the test relay 120 will be held energized until the cont-acts ot an idle selector are engaged. The test contact of' such a selector will not be connected to ground and relay 120 will retract armature, opening the circuit for the escape magnet 119 which, in turn retracts its armature and moves the side switch to pcsit-ion 3 The vertical oil-.normal contact 12a is closed during the upward' movement of the switch and opens on the tenth vertical step in order to prevent jamming' of the switch in case n.0 idle trunk is found.

The connection from the manual. or toll switchboard has now been connected to the connector switch in the automatic exchange. It desired, however, other selectorswitches may be interposed between the selector G- and connector H.

Assuming, however, that the present system discloses a thousands line exchange and that the series ef impulses which o perated the selector switch Gr were the hundred impulses, the operator will new operate her impulse sender to send the tens iin-A pulses, causing a. series of int-errupvtionsv in the circuit o 'f relay 109 as b eiore. lith the first retraction of the armaturel of relay 109, circuits will be completed from battery, through the release relay 131, rotary stepping magnet 132 and the escape relay 133. The circuit Jfor the rotary magnet 132y passes through side switch wiper 1341, where it joins the lead from relay 133. The circuit ijs then extended through the left armature and back contact of relay 135, to the lead from relay 131, the circuit being continued through brush 113, wipers' 121 and 113, front contact of relay 110 and the back contact et' relay 109.v Magnet 132 and relays 131 and 133 are all energized. Relay 1131 will be held up by the path to ground through resistance 115 in the same manner as relay 11.4. Relay 133 being slow to release its armature, remains up during the series ot' impulses. The armature of rotary stepping magnet 132 is alternately attracted and retracted, causing the connector l'nfushes 136,v 137 and 138 to be move-d from group' tc group of the terminal contacts. of the lines terminating thereat. Upon the termination et the series of impulses, the

rotary stepping magnet 132 will remain deenerg'ized. thus stopping the switch bruSlles in yoperative, relation to the tens groupof contacts. in whch the wanted line terminates. lVlie-n the arma-ture of relay 133 was attracted. it completed a circuit from battery, thruig'h escape magnet 139 and the alternate Contact and armature of relay 133., to ground, causing the energization of the. es- `ape magnet. Upon `the tei'nji-ination ot the series ci impulses. relay 133 will retract its armature, opening the circuit for the escape magnet 133 and permitting the side switch to more to position 2.

The operator will now send the last or units series of impulses. lVith the first deenergizaticn of relay 109', the vertical mag'- net 1t() and relay will be energized in a manner similar to that described in connection with rotary magnet 132 and relay 133 upon sending the tens series oit impulses..

The brushes of the connector switch will now be stepped from line to line of the desired group until they are positioned on the cont'acts of the wanted subscribers line.

la the wanted line is already busy, the sleeve or test vterminal thereof will be connected to ground through the brush 138 and wiper 1-11 in positions 3 and 4 of the connecter switch connected thereto. It, however, the line is idle, its testterminal will be connected. to battery only, through its cut? otl' relay 112. lVhe.. relay 133 was energized due to sending the units series of impulses, the escape magnet 139 was energized in the same manner as before. Now upon the retraction of the armature cf relay 133 at the end ot the units series of' impulses, a. circuit is completed rombattery, through the 'winding` of magnet 139, the normal contacts/ot relay 133, test relay 135 and its right normal contact, wiper 141,. and brush 133,` to the test terminal of the cal-led line.

is soon as the impulse sender has been actuated. by the .operator at the manual izo switchboard to send out impulses in accordance with the number of the desired subscriber, plug 20 of the dialing or calling cord is removed from jaclf. 1 and plugged into the calling or dialing jack o't the nent idle trunk hunting circuit, such as C. Removal of the plug 20 from jaclr 1 linterrupts the circuit :tor relays 8 and 41. Relay 41, upon deenergization, completes a circuit at its armature and back contact for relay 42 as follows: grounded battery, winding oi relay 42, back contact and armature oi relay 41, normal contact ot relay 40, terminal 30, brush lower inner armature and iront contact ot relay 9, to ground.v Energization ot relay 42 thus disconnects the impulse repeating means associated with lthe trunk circuit 'from said trunk circuit and together with deenergiza-A tion of relay 8 entends the operators telephone circuit at the manual switchboard over the talking conductors to the automatic switches atl the automatic telephone e2;- change. Lamp 49 is also extinguished.

As before stated, it a called line is busy, its multiple test terminals will be connected to ground. A test relay 135 will be energized and ink attracting its armature will I complete a locking circuit tor itselil and magnet l139 through its alternate contacts and the side switch wiper 1517and its second contact. Magnet 139 now being energized and the side switch being in position 2, the busy tone of device 143 will be connected to the talking circuit through the lett armature and tront contact ot escape nmgnet 139 and side switch wiper 144.

lt will be noted that the busy tone device was connected to the upper conductor of the talking `circuit during the sending' of the last series of impulses but as the talking circuit is not extended to 'the operators telephone circuit until after the impulses have been sent and the line tested, and as the side switch would be moved to position 3 simultaneously with testing of the line, the operator would not hear the busy signal it the wanted line was idle.

However, assumingthat the line is busy and that the operator hears the busy signal. Plug 19 is withdrawn from the ack 4. Re lays 14, 8, 9 and 42 are thereupon deenergized, causing in turn the deenergization ot relay 1.09. Relay 109, upon deenergisation, interrupts the circuit ot relay 110 whichretracts its armature, thus opening the holding circuit for relay 114 of the trunk switch and the relay 131 of the connector switch. Relay 114 in retracting its armature completes a circuit from battery, through release magnet 127, rotary oil-normal contact 128 closed on the first rotarystep, and the armature and back contactl ot relay 114, to ground, thus causing the restoration oi the trunk switch. Relay 131 in retracting its armature, completes a circuit from battery, through release relay 145, rotary oil-normal contact 146 closed on the first rotary step, the armature and back contact of relay 131, to ground, thus causing the restoration ot the connector switch. lt will be noted that the holding circuit for the escape magnet 139 and the test relay 135 of the connector switch is maintained until the switch is re-` leased and the side switch brushes are maintained operated until the switch is yreleased and tne side switch brushes are returned to normal, thus preventing ringing on the busy lines. i

Assuming now that the wanted line is idle, its test connector will not be connected to ground. 'lhus relay 135 will not be energized and the escape magnet 139 will retract its armature moving thev side switch to position 3. ln position 3, acircuit is closed trombatteryu through the escape magnet 139, the armature and Contact ot relay 147 and the side switch wiper 151 in its third position, to ground. The escape magnet 139 attracts its armature and completes a circuit from the generator 148, through trip relay 147 and the right armature and front contact ot the escape magnet 139, side switch wiper 149 in its third position, brush 137, over the right side of the subscribers line, through the bell of the wanted subscribers substation set, back over the lett side ot the line, brush 136 and side switch wipers 150 and 151 and third contacts, to ground. This will cause the operation of the bell of the wanted subscriber. The busy tone will not y be connected to the talking conductor at this time, as the side switchis in position 3.

Upon the closing ot the called subscriber-s switchhook, the increased flow oi' current through the trip relay 147 will cause it to attract its armature, thus interrupting the circuit for the escape magnet 139 and causing the side switch to move to position 4, in which position the talking circuit will be established from the calling to the called line. Talking current is supplied to the called subscriber through the windings of the repeating coil in the cord circuit at the manual switchboard. Busy potential will be supplied to the test contact ot the called line through the side switch wipers 141 in positions 3 and 4. @n completion ot conversation, the operator removes plug 19 from jack 4 at the switchboard, thus causing successively the deenergization ot relays 14, 9 and 42 at the manual exchange, which in turn causes the deenergization of relay 109 at the automatic exchange. Relay 109, upon deenergization, causes restoration of the trunk and connector switches over paths previously traced and the system is then ready for another call.

lhat is claimed is:

1. In a telephone exchange system, a

ilo

manual telephone exchange, an automatic telephone exchange, a plurality of trunk circuits each including a pair of talking conductors and a non-talking conductor, extending between said exchanges, an impulse sending device at said manual otlice, means for associating said impulse sending device with an idle one of said trunk circuits, a repeater associated with said trunk circuit arranged to receive impulses from said impulse sending device over a talking' conductor and to re-transmit the impulses to said automatic exchange over a noirtalking conductor, and means for disassociat-ing said repeater from said connecting circuit after said impulses have been sent.

2. In a telephone exchange system, a manual telephone exchange, an automatic telephone exchange, a plurality oit trunk circuits :for extending connections from said manual exchange to said automatic exchange, a trunk linding switch for automatically selecting an idle trunk circuit, a. link circuit at the manual exchange for connection with the trunk linding switch, an impulse sender associated with the link circuit, automatic switches at the automatic exchange adapted to be controlled by said impulse sender, and means associated with said trunk circuit for repeating impulses received over a talking' conductor of said trunk finding switch and said trunk to a non-talking conductor leading to said automatic exchange for controlling the automatic switches thereat.

3. In a telephone exchange system, a manual telephone exchange, an automatic telephone exchange, a plurality of trunk circuits including a pair of normally open talking conductors and a non-talking conductor extending between said exchanges, an impulse-sending device at said manual office, means tor connecting said impulse sending device with an idle one of said trunk cir= cuits, and a repeater connected to a talking conductor ot' said trunk circuit arranged to receive impulses from said impulse sending device over a talking conductor and to retransmit the impulses to said automatic exchange over a non-talking conductor, said repeater being disconnected from said talking conductor after the impulses have been sent.

4. ln a telephone exchange system, a manual telephone exchange, an automatic telephone exchange, a plurality of trunk circuits, each including a pair of talking conductors and a non-talking conductor, extending between said exchanges, an impulse sending device at said manual otlice, means for connecting said impulse sending device with an idle one ot said trunk circuits, a repeater associated with a talking conductor of said trunk circuit arranged to receive impulses from said impulse sending device over a talking conductor and to re-transmit the impulses tosaid automatic exchange vover, a non-talking conductor, and means for 'disf associating' ysaid impulse repeating relay from said trunk circuit after the impulses have been sent. Y i

5. `ln a telephone exchange system, in combination, a plurality or' trunk circuits comprising a pair of talking conductors and a non-talking conductor extending between a manual exchange and an automatic exchange, a link circuit and an impulse sender at said manual exchange, a trunk finding circuit at said manual exchange, means responsive to the connection of said link circuit with said trunk linding circuit for connecting said link circuit and impulse sender with an idle trunk circuit, means for placing a busy test on the selected trunk circuit, switches at said automatic exchange adapted to operate by impulses transmitted there to over a non-talking conductor, and means associated with said trunk circuit for repeating impulses received from said impulse sender over a non-talking conductor of said trunk circuit and for maintaining the busy test on a selected trunk during the transmission of the impulses,

6. ln a telephone exchange system a plurality of trunk circuits each comprising a pair of talking conductors and a non-talking conductor and each terminating in a numerical switch, a link circuit terminating in a non-numerical switch, a cord circuit and an impulse sender, means operative when the cord circuit and the sender are connected to the link circuit for causing said non-numerical switch to select an idle one of the trunk circuits, means for placing a busy test on the selected trunk circuit, an impulse repeater associated with the selected trunk circuit controlled by said sender for intermittently opening the non-talking conductor of the selected trunk circuit to set the switch associated therewith, and means for maintaining the busy test on the selected trunk circuit during the operation of the sender.

7. In a telephone exchange system a plurality of trunk circuits each comprising a pair of talking conductors and a non-talking conductor and each terminating in a numerical switch, a link circuit terminating in a non-numerical switch, a cord circuit and an impulse sender, means operative when the cord circuit and the sender are connected to the link circuit for causing the nonnumerical switch to select an idle one of the trunk circuits, means for placing a busy test on the selected trunk circuit, a relay associated with the non-talking conductor of the selected trunk circuit for controlling the setting of said switch, a circuit extending' through the test contact of said nonnumerical switch and including the winding of said relay, and a second relay associated With the selected trunk circuit controlled by said sender for repeating impulses to sai` first named relay, the contacts for said second named relay interposed between the test Contact of said n0n-numerieai switch and said rst` named relay so that during the operation of theV sender the busy test c0ndi- CLARENCE B. FOWLER. 

